In order to investigate the effects of the straw decomposition on soil physical, chemical properties and biological properties of pear orchard, field experiments were carried out, treatments were included plastic mulching(CK), straw mulching(S), straw mulching + decomposing bacterial manure(S-BM), double straw mulching + decomposing bacterial manure(2S-BM). The results showed that the decomposition rate was 62.4% for S-BM treatment, while were 50% for S and 2S-BM treatments. Release rates of nitrogen and potassium of S-BM treatment were the highest under straw mulching after 150 d. Straw mulching increased soil lowest temperature, decreased soil highest temperature and temperature amplitude. The content of soil dissolved organic carbon increased while soil bulk density decreased significantly in 2S-BM treatment. Straw mulching increased soil organic carbon content at 0 – 5 cm, 2S-BM treatment enhanced soil available nutrient content at 0 – 15 cm, and S and S-BM increased soil available potassium content at 0 – 5 cm, significantly. 2S-BM treatment increased the number of soil bacteria, fungi and the contents of soil microbial biomass carbon and nitrogen in the late growth stage of pear tree. In addition, pear yields of 2S-BM, S-BM and S treatments were 86.9%, 17.8% and 28.7% higher than the CK respectively. Straw mulching improved soil properties from top to bottom, and the effect of soil improvement was very obvious when the amount of returning straw was 45 000 kg/hm2 in pear orchard.